Adjust oven rack to middle position and heat oven to 375 degrees.

Spread oats evenly on rimmed baking sheet and bake until fragrant and lightly browned, about 10 minutes, stirring halfway through baking.

Transfer sheet to wire rack and let oats cool completely.

Transfer half of cooled oats to bowl and stir in water.

Cover bowl with plastic wrap and let sit until water is absorbed, about 10 minutes.

Whisk almond flour, flour blend, salt, baking powder, xanthan gum, and nutmeg together in medium bowl.

Whisk melted butter, brown sugar, granulated sugar, egg and yolk, oil, and vanilla in large bowl until well combined and smooth.

Stir in flour mixture, oat-water mixture, and remaining toasted oats using rubber spatula until soft, homogeneous dough forms.

Fold in raisins.

Cover bowl with plastic and let dough rest for 30 minutes.

Heat oven to 325 degrees.

Line 2 baking sheets with parchment paper.

Working with 2 generous tablespoons dough at a time, roll into balls and space them 2 inches apart on prepared sheets.

Using bottom of greased measuring cup, press dough to ½-inch thickness.

Bake cookies, 1 sheet at a time, until edges are set and beginning to brown but centers are still soft and puffy, 22 to 25 minutes, rotating sheet halfway through baking.

Let cookies cool on sheet for 5 minutes, then transfer to wire rack.

Serve warm or at room temperature.